Nanoparticles lethal to Arctic ecosystem

Emma Woollacott, 7th April 2011

Queen’s University researchers have discovered that nanoparticles - now found in everything from socks to suntan lotion - may be causing irreparable harm to soil systems and the environment.

The team started by acquiring a sample of soil from a remote Arctic site - as uncontaminated as possible. They then added three different types of nanoparticle, including silver; millions of tonnes of this are produced every hear, mainly for use as an anti-bacterial agent.

The soil samples were then left for six months to see how the addition of the nanoparticles affected the microbe communities. What the researchers found was both remarkable and concerning, they say.

"We hadn’t thought we would see much of an impact, but instead our results indicate that silver nanoparticles can be classified as highly toxic to microbial communities," says says Virginia Walker, a professor in the Department of Biology.

"This is particularly concerning when you consider the vulnerability of the Arctic ecosystem."

The original analysis of the uncontaminated soil had identified a beneficial microbe that helps fix nitrogen to plants. As plants are unable to fix nitrogen themselves and nitrogen fixation is essential for plant nutrition, the presence of these particular microbes in soil is vital for plant growth.

But the analysis of the soil sample six months after the addition of the silver nanoparticles showed that only negligible quantities of the important nitrogen-fixing species remained. Laboratory experiments showed that they were more than a million times more susceptible to silver nanoparticles than other species.

She said that widescale use of nanoparticles could turn out to be as deadly a mistake as thalidomide.